U.S. patent number 4,348,292 [Application Number 06/197,918] was granted by the patent office on 1982-09-07 for multi-layered liquid detergent-builder concentrate compositions which on addition to water produce stable cleaning solutions.
This patent grant is currently assigned to Walton-March, Inc.. Invention is credited to Martin E. Ginn.
United States Patent |
4,348,292 |
Ginn |
September 7, 1982 |
Multi-layered liquid detergent-builder concentrate compositions
which on addition to water produce stable cleaning solutions
Abstract
A detergent system, especially adapted for single-use
applications, in the form of a fluid-tight container having two
separate layers of liquid compositions therein, one of the liquid
compositions comprising a predetermined volume of a concentrate of
a surfactant or detergent, and the other composition comprising a
predetermined volume of a concentrate of an inorganic builder. The
compositions are characterized in that, if mixed together in their
concentrated form, they would be incompatible or immiscible, and
would result in a non-homogeneous mixture. However, the
compositions are so related as to the ingredients and proportions
thereof, that when the separate layers are poured from the
container into a predetermined volume of a diluent such as water, a
stable cleaning or detergent solution or dispersion is obtained in
ready-to-use form.
Inventors: |
Ginn; Martin E. (Skokie,
IL) |
Assignee: |
Walton-March, Inc. (Highland
Park, IL)
|
Family
ID: |
22731269 |
Appl.
No.: |
06/197,918 |
Filed: |
October 17, 1980 |
Current U.S.
Class: |
510/406; 510/191;
510/207; 510/417; 510/423 |
Current CPC
Class: |
C11D
11/0094 (20130101); C11D 17/043 (20130101); C11D
17/0017 (20130101) |
Current International
Class: |
C11D
11/00 (20060101); C11D 17/04 (20060101); C11D
17/00 (20060101); C11D 017/04 (); C11D
011/00 () |
Field of
Search: |
;252/90,92,153,546,135,174.21,547,DIG.14,174 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Willis, Jr.; P. E.
Attorney, Agent or Firm: Wallenstein; Sidney
Claims
What is claimed is:
1. A detergent system for single-use applications in providing a
substantially homogeneous aqueous solution or dispersion of
predetermined composition to be used for detergent, cleaning, or
the like, purposes, comprising a fluid-tight container having at
least two separate layers of liquid compositions therein, one of
said layers comprising, as an essential ingredient, a predetermined
proportion of a concentrate of at least one surfactant which is
soluble or readily dispersible in water; and another of said layers
comprising, as an essential ingredient, an aqueous solution, in the
form of a concentrate, which includes a predetermined proportion of
at least one detergent builder; the compositions of said separate
layers being of a character such that, if mixed together in their
concentrated form, they would be incompatible or immiscible and the
resulting mixed composition would be non-homogeneous; said liquid
compositions of said separate layers being so related as to the
ingredients and proportions thereof that, when essentially all of
the liquid contents of the layers in said container are poured into
a predetermined proportion of water, a final essentially stable
solution or dispersion is obtained in ready-to-use form for the
intended detergent, cleaning, or the like, use of the thus finally
produced stable solution.
2. A system according to claim 1 wherein the surfactant concentrate
is a nonionic, anionic, cationic or amphoteric surfactant, or a
compatible mixture thereof.
3. A system according to claim 2 wherein the nonionic, anionic,
cationic or amphoteric surfactant, or compatible mixture thereof
comprises from about 50% to about 99% of the surfactant
concentrate.
4. A system according to claim 1 wherein the detergent builder
concentrate includes at least one alkali metal or ammonium
carbonate, phosphate, sulfate or silicate, the proportion thereof
in the concentrate being in the range of about 30% to about 80%, by
weight, of the concentrate.
5. A system according to claim 1 wherein the fluid-tight container
comprises a flexible packet formed of a heat-sealable plastic sheet
material.
6. A system according to claim 1 wherein the use-dilution range of
the total concentrate system in the container is from about 1 of
the concentrate system to about 500 of the diluent used to form the
final ready-to-use solution or dispersion.
7. A system according to claim 1 wherein the surfactant concentrate
layer comprises about 99%, by weight, of a water soluble condensate
of an alkylphenol with from about 5 to 15 moles of ethylene oxide,
and the builder concentrate layer comprises about 30%, by weight,
of a mixture of an alkali metal carbonate, an alkali metal
hydroxide and an alkali metal salt of ethylenediaminetetraacetic
acid.
8. A system according to claim 1 wherein the surfactant concentrate
layer comprises a major proportion of a mixture of a nonionic
surfactant and a cationic surfactant, the nonionic surfactant
comprising a water soluble condensate of an alkylphenol with from
about 7-12 moles of ethylene oxide, and the cationic surfactant
comprising a water soluble quaternary ammonium salt.
9. A system according to claim 1 wherein the builder concentrate
layer comprises a minor proportion of a polybasic organic acid or
an alkali metal salt thereof.
10. A system according to claim 1 wherein the surfactant
concentrate layer contains essentially no water.
11. A system according to claim 1 wherein the surfactant
concentrate layer comprises less than about 10%, by weight, of
water.
12. In a method of preparing a substantially homogeneous aqueous
solution or dispersion of predetermined composition useful for
detergent or cleansing purposes which comprises providing a
fluid-tight container having at least two separate layers of liquid
compositions therein, one of said layers comprising, as an
essential ingredient, a predetermined proportion of at least one
water-soluble surfactant as a concentrate thereof in the form of a
liquid product which is soluble or readily dispersible in water,
and the other of said layers comprising, as an essential
ingredient, a water solution, in the form of a concentrate, which
includes a predetermined proportion of at least one inorganic
builder; the compositions of said separate layers being of a
character such that, if mixed together in their concentrated form,
they would be incompatible or immiscible and the resulting mixed
composition would be nonhomogeneous; providing a predetermined
proportion of water in a suitable second container; and then
pouring into said water essentially all of the liquid contents of
the layers in said fluid-tight container to produce a final, dilute
essentially homogeneous stable solution or dispersion in
ready-to-use form for intended detergent or cleaning use of said
thus finally produced aqueous composition.
13. A method according to claim 12 wherein the container comprises
a fluid-tight packet formed of a flexible, heat-sealable plastic
sheet material.
14. A method according to claim 12 wherein the use-dilution range
of the total concentrate system in the container is from about 1 of
the concentrate system to about 500 of the diluent used to form the
final ready-to-use solution or dispersion.
15. A method according to claim 12 wherein the volume of the total
concentrate system in the container is from about 1 ounce to about
1 gallon.
Description
The present invention relates to detergent or cleaning concentrates
especially adapted for single-use applications.
Generally speaking, in formulating liquid detergents and cleaners
to provide an end product which is homogeneous in appearance, the
ability to concentrate the ingredients comprising the formulation
is limited by the degree of compatibility of the ingredients.
Typically, conventional formulation approaches involve, for
example, dissolving organic surfactants and inorganic builder
components in aqueous media using coupling solvents and/or
hydrotropes to attain a homogeneous and stable dispersion of the
ingredients. This practice can give rise to problems because the
organic surfactants tend to "salt out" of solution due to the
presence of the alkaline inorganic salts employed in the builder.
Thus, even when cosolubilizing agents are used, there is a critical
upper limit as to the quantity of the functional components which
can be maintained in dispersion in the end product. In a sense,
there is what might be called a "compatibility barrier" in the
conventional formulation of liquid detergents and cleaners. A
formulator, therefore, has considerable difficulty in utilizing
larger concentrations of the more active components. Wholly apart
from the ingredient incompatibility and concentration of ingredient
problems encountered with conventional formulating practices, such
practices have important economic disadvantages, chief among which
are the need for cosolubilizing agents, and the comparatively large
volumes of water required to attain a homogeneous end product. In
this latter connection, it should be noted that typical liquid
detergent and cleaning formulations contain 50%, or more, water,
while the active surfactant content is of the order of 16%, or
less. Cosolubilizing agents such as coupling solvents and
hydrotropes, of course, represent an added raw material cost, while
the need for appreciable volumes of water adds to the material
handling costs and at the same time entails the use of containers,
or packaging, of a correspondingly larger size to accommodate the
end product.
In accordance with the present invention, a system has been evolved
for providing liquid detergents and cleaners in a highly
concentrated form which eliminates the need for cosolubilizing
agents and large volumes of water. The resulting significant
savings in starting material and material handling costs are
augmented by the fact that the system enables smaller and less
costly containers, or packaging, to be used to hold the
concentrates. What is more, the systems provide stable,
ready-to-use solutions which not only are less costly on a unit
volume basis than is the case with conventional homogeneous
cleaning solutions, but, also, show surprisingly improved cleaning
efficiency on a unit volume basis over homogeneous solutions.
The system of the present invention is especially adapted for
single-use applications to provide a substantially homogeneous,
dilute solution or dispersion of predetermined composition to be
used for detergent, cleaning, or the like, purposes. The system
comprises a fluid-tight container having at least two separate
layers of liquid compositions therein, one of the layers
comprising, as an essential ingredient, a predetermined quantity of
a concentrate of at least one surfactant which is soluble or
readily dispersible in a diluent such as water. Another of the
layers in the container advantageously comprises, as an essential
ingredient, a solution or dispersion, in the form of a concentrate,
which incorporates a predetermined quantity of at least one
detergent builder. The compositions of the separate layers in the
container are of a character such that, if mixed together in their
concentrated form, they would be incompatible or immiscible, and
the resulting mixture would be non-homogeneous. The compositions of
the separate layers, however, are so related as to the components,
or ingredients, and proportions thereof that when essentially all
of the liquid contents of the container are poured into a
predetermined quantity of a diluent such as water, a final,
essentially stable solution or dispersion is obtained in
ready-to-use form. In marked contrast to typical homogeneous
formulations, the active surfactant concentrate portion of the
system, in most instances, will contain less than 10%, usually 4 or
5%, of water, and, in other cases, depending upon the nature of the
ingredients employed, will contain no added water. The system can
be formulated to provide, in ready-to-use form, stable solutions
useful as hard surface cleaners, degreasers, bowl cleaners, floor
wax removers, liquid dishwashing detergents, commercial or
household heavy duty laundry liquids, concentrated liquid hand
soaps, carpet shampoo concentrates, high strength metal cleaners,
car wash concentrates, and the like.
In accordance with a preferred embodiment of the invention, the
system comprises a water soluble surfactant concentrate layer
component and a water soluble builder concentrate layer component
packaged in a suitable, flexible or rigid plastic liquid-tight
container. Generally speaking, the ingredients employed in
formulating the surfactant concentrate layer will be dependent upon
the use to which the finally produced stable, ready-to-use solution
is to be put. Thus, for example, if the solution is to be used as a
hard surface cleaner, the surfactant concentrate layer will
advantageously comprise as an essential ingredient a major
proportion of a water soluble nonionic surfactant or a compatible
mixture of nonionic surfactants. On the other hand, if, for
example, the ready-to-use solution is to be employed as a
degreaser, the surfactant concentrate layer desirably will comprise
a major proportion of a compatible mixture of water soluble
nonionic, anionic, cationic or amphoteric surfactant materials or a
mixture of nonionic and anionic surfactants.
Exemplary of water soluble nonionic surfactants useful for the
purposes of this invention are polyglycol esters of higher straight
and branched chain aliphatic alcohols and polyglycol esters of
higher fatty acids, in which the alcohol group and the fatty acid
group, respectively, comprises 8 to 20, or more, carbon atoms and
which contain 10 to 50 ethylene oxide units per molecule.
Especially preferred nonionic surfactants are the water soluble
condensates of alkylphenols such as octyl- or nonylphenol with from
about 5 to about 15 moles of ethylene oxide. Also useful are the
numerous compounds obtained from the reaction of alkanolamines and
fatty acids, and the ethylene oxide condensates thereof.
Water soluble anionic surfactants which can be used include alkyl
aryl sulfonates, in particular alkylbenzene, especially linear
monoalkyl benzene, sulfonates in which the alkyl group contains
from 8 to 20 carbon atoms, specific examples being n-dodecylbenzene
sulfonate and n-octadecylbenzene sulfonate; higher aliphatic
sulfates and sulfonates in which the aliphatic radical comprises
from 8 to 20 carbon atoms such as lauryl sulfate or lauryl
sulfonate; and higher fatty acid amides in which the acyl group
contains from 8 to 20 carbon atoms such as tallow fatty acid amide,
cocoa fatty acid amide, and the like. The sulfates and sulfonates
are commonly used in the form of alkali metal salts, although the
corresponding salts of ammonium or organic bases such as
ethanolamine, triethanolamine, and the like may also be used.
Cationic surfactants useful in formulating the surfactants
concentrate layer of the system include quaternary ammonium salts
represented by the formula: ##STR1## where: R.sub.1 is hydrogen,
alkyl or alkylol; R.sub.2 and R.sub.3 are lower alkyl or alkylol,
or aryl or aralkyl; R.sub.4 is a long chain alkyl radical
containing from 8 to 22, preferably 12 to 15 carbon atoms in
straight or branched chain arrangement, with or without aryl or
alkaryl substituents; and A is an anion such as halogen, sulfate,
acetate, hydroxyl, or the like. Specific examples of such salts are
cetyl-dimethyl-benzyl-ammonium chloride, didodecyl-benzyl-methyl
ammonium chloride and dodecyl-dimethylethylbenzyl ammonium
chloride, to mention a few. Another group of quaternary substituted
ammonium compounds which can be used are heterocyclic derivatives
wherein N is an element in a heterocyclic ring. Typical of this
group are lauryl morpholinium, imidazolium, pyridinium and
quinolium compounds specific examples of which are N-benzyl-N
higher alkyl morpholinium chloride and N-laurylmethyl pyridinium
chloride.
Amphoteric surfactants which can be used to formulate the
surfactant concentrate layer of the system include betaine and
various betaine compounds such as coco betaine, tallow betaine,
cocoyl amido propyl betaine, laurylamidipropyl betaine, to mention
a few. Also useful as amphoterics are substituted imidazolines
exemplified by mono- and dicarboxyl coco imidazoline, lauryl
imidazoline, coco imidazoline, and the like.
The active surfactant ingredient, that is, the nonionic, anionic,
cationic or amphoteric surfactant, or a compatible mixture thereof,
employed in preparing the surfactant concentrate layer of the
system comprises, as indicated hereinabove, a major proportion of
the layer. The generally optimum objectives of the invention are
attained with active surfactant concentrations of from about 50% to
upwards of about 99%, by weight, of the surfactant concentrate
layer. The finished surfactant concentrate layer desirably includes
minor amounts of materials which will make the stable, ready-to-use
solution prepared from the system of the present invention more
effective and more attractive. The following are mentioned by way
of example. A defoamer such as silicone and silicone emulsions, and
fluorescers, perfumes and dyes. The concentration of such additives
in the layer will range from about 0.01% to about 8 or 10%, by
weight of the concentrate. Other additives, of course, can be used
without departing from the spirit and scope of the invention.
The ingredients employed in formulating the water soluble builder
concentrate layer of the system, for optimal results, will be
dictated in large measure by the composition of the surfactant
concentrate layer. As indicated hereinabove, the surfactant
concentrate layer and the builder concentrate layer are of a
character such that, if mixed together in their concentrated form,
they would incompatible or essentially immiscible, and the
resulting mixture would be non-homogeneous. However, the
ingredients comprising each layer are so related with respect to
their functional properties and their proportions in the layers
that when both layers are poured into a predetermined volume of a
diluent such as water, a final essentially stable detergent or
cleaning solution, or dispersion, is produced in ready-to-use
form.
By way of illustration, in formulating a builder concentrate layer
for use with a surfactant concentrate layer intended for producing
a stable detergent or cleaning solution for use as a hard surface
cleaner, the active ingredients of the builder concentrate layer
will advantageously comprise an alkali metal builder salt such as
sodium or potassium carbonate, an aqueous solution of an alkali
metal hydroxide exemplified by a 50% solution of potassium or
sodium hydroxide, and a soluble aminopolycarboxylate salt such as
an alkali metal salt of ethylenediaminetetraacetic acid. In
formulating a builder concentrate layer for use with a surfactant
concentrate layer to produce a ready-to-use solution to serve as a
degreaser, the builder layer desirably will be formulated to
include a polybasic organic acid such as citric acid, or an alkali
metal salt of such an acid, an aqueous solution of an alkali metal
hydroxide, an aminopolycarboxylate salt, and a small amount of a
stabilizer such as polyvinyl pyrrolidone. Sufficient water is added
to maintain the active ingredients comprising the builder
concentrate layer in solution. Generally speaking, the proportion
of active materials in the builder concentrate layer will range
from about 20% to about 80%, usually about 30% to about 40%, by
weight, of the aqueous concentrate builder layer.
Other alkali metal builder salts which can be used in formulating
the builder concentrate layer include alkali metal phosphates,
sulfates, and silicates exemplified by disodium orthophosphate,
sodium metaphosphate, sodium tripolyphosphate, sodium sulfate and
sodium silicate, to mention a few. The corresponding ammonium salts
also are useful. Exemplary of aminopolycarboxylate salts which can
be used are the sodium, potassium and alkanolammonium salts formed
with ethylenediaminetetraacetic acid,
N-(2-hydroxyethyl)ethylenediaminetetraacetic acid and
nitrilotriacetic acid. In addition to the foregoing, amine salts,
alkali metal salts and ammonium salts of gluconic acid can be
incorporated into the builder concentrate layer to reduce possible
skin irritation.
The volume ratio of surfactant concentrate layer to builder
concentrate layer of the system of the present invention can range
from about 1:9 to 9:1, again depending upon the end use of the
stable solution produced by the system. The total volume of the
concentrated layers in the container comprising the system can vary
widely, again, depending upon the final use-dilution volume
required. Generally speaking, for most purposes, the total volume
of the concentrate layers will be of the order of 1 to 2 ounces up
to a gallon for large scale cleaning operations. The use-dilution
ranges, that is, the amount or volume of diluent such as water to
be used in producing a stable ready-to-use solution with the
concentrates comprising a particular system also will depend upon
the end use of the solution. In broad terms, the use-dilution
ranges for good performance will be of the order of about 1 of the
concentrate system to about 30 to about 500 of water.
The fluid-tight containers comprising the system may be fabricated
of glass or plastic. For average cleaning jobs, the containers
advantageously will be in the form of a flexible, single-use bag or
packet made of a thermoplastic sheet material such as polyethylene.
Heat sealable containers of this type will contain from about 1 or
2 to about 6 ounces of the concentrate layers, and, while resistant
to tearing, can be readily opened. The concentrate layers can be
injected into the bag or packet, and the bag or packet heat sealed,
with conventional equipment.
The following compositions are illustrative of the system of the
present invention. The percentages are given on a weight basis.
EXAMPLE I
______________________________________ Hard Suface Cleaner
Surfactant Conc. Layer Builder Conc. Layer Ingredients %
Ingredients % ______________________________________ 1. 7-12 Mole
ethoxylate of 1. Water 67.90 lauryl alcohol (nonionic) 98.95 2.
Potassium 2. Herbal Pine Perfume 1.00 Carbonate 6.60 3. Soap Green
Dye 0.05 3. Tetrasodium ethylenediamine- tetraacetate (Na.sub.4
EDTA) 7.20 4. Potash (50% KOH in water) 18.30
______________________________________
EXAMPLE II
______________________________________ Hard Surface Cleaner
Surfactant Conc. Layer Builder Conc. Layer Ingredients %
Ingredients % ______________________________________ 1. Linear
fatty alcohol 1. Water 24.00 ethoxylate (Polyfac 2. Potassium
Carbonate 26.00 LA3) 98.95 3. Potash solution 18.00 2. Perfume 1.00
4. Na.sub.4 EDTA solution 3. Dye 0.05 (38%) 32.00
______________________________________
EXAMPLE III
__________________________________________________________________________
Degreaser Surfactant Conc. Layer Builder Conc. Layer Ingredients %
Ingredients %
__________________________________________________________________________
10 Mole ethoxylate of 1. Water 72.00 nonylphenol (nonionic) 69.047
2. Polyvinyl Pyrrolidone 1.00 N-Tallowdimethylbenzyl 3. Na.sub.4
EDTA 10.00 ammonium chloride 2.25 4. Citric Acid 8.00
N-Cetyldimethylethylbenzyl 5. KOH (Potassium ammonium chloride 2.25
hydroxide) 9.00 Water 4.45 Betaine surfactant 5.00 Silicone
surfactant 2.00 Imidazoline derivative of tall oil 3.00 Silicone
foam inhibitor 0.003 Monoethanolamine 12.00
__________________________________________________________________________
EXAMPLE IV
______________________________________ Floor Finish Remover
Surfactant Conc. Layer Builder Conc. Layer Ingredients %
Ingredients % ______________________________________ 1.
Monoethanolamine 30.47 1. Na.sub.4 EDTA 17.01 2. Butyl Cellosolve
21.50 2. Potassium 3. Dodecylbenzene sulfonic hydroxide 10.14 acid
6.91 3. Potassium 4. Fatty alkanolamide 18.42 Carbonate 11.90 5.
Nonylphenol ethoxylate 4. Water 60.95 (10 moles ethylene oxide)
22.30 6. Silicone defoamer 0.25 7. Dye trace 8. Fragrance 0.15
______________________________________
EXAMPLE V
______________________________________ Bowl Cleaner Surfactant
Conc. Layer Builder Conc. Layer Ingredients % Ingredients %
______________________________________ 1. 7-12 Mole ethoxylate 1.
Water 63.33 of octyl alcohol 56.20 2. Sodium Gluconate 16.67 2.
7-12 Mole ethoxylate 3. Potassium Carbonate 20.00 of octyl phenol
20.69 3. Isopropanol 1.41 4. Perfume 7.14 5. Dye 0.28 6.
Cocodimethylbenzyl- ammonium chloride 3.57 7. Laurylmethylethyl-
benzylammonium chloride 3.57 8. Water 7.14
______________________________________
In order to demonstrate the improved cleaning efficiency of stable
detergent or cleaning solutions or dispersions produced with the
systems of the present invention over the cleaning efficiency of
conventional homogeneous detergent or cleaning solutions, as well
as to show the cost advantages afforded by the systems over
conventional homogeneous solutions, comparative performance/cost
tests were carried out using an all-purpose cleaner prepared with a
system of this invention and a conventional all-purpose
cleaner.
COST/PERFORMANCE COMPARISON
Table I gives the formula, cost data, and the cleaning efficiency
at use-dilution for an all purpose cleaner produced from a system
of the invention. At a dilution ratio of 1/256, the cleaning
efficiency (C.E.) of this formulation was 80 percent and the cost
of chemicals for one gallon of this use-dilution was $0.0114.
Comparative data for a homogeneous formulation, using the same raw
materials plus solubilizers (hydrotropes or solvents), are given in
Table II. The homogeneous formulation required a 1/20 dilution to
yield a C.E. of 77.5% at a cost of $0.0602/use-dilution gallon.
Thus, a homogeneous preparation had to be 12.8 times more
concentrated at use-dilution to yield similar cleaning, and this
costs approximately six-times more than the system of this
invention.
TABLE I ______________________________________ All Purpose Cleaner
$ $ % cost cost/100 lbs. ______________________________________
Builder Concentrate Water 21.40 0.0001 0.0021 Potassium Carbonate
9.00 0.315 2.835 Potassium Citrate 9.00 0.840 7.560 Caustic Potash
10.60 0.1645 1.7437 Surfactant Concentrate Nonyl Phenol ethylene
oxide 35.00 0.4525 15.8375 Diethylene glycol monomethyl ether 14.45
0.4200 6.069 Perfume 0.50 4.0000 2.0000 Dye 0.05 9.7080 0.4854
100.00 $36.5327 ______________________________________ Cost per
pound = 0.3653 (0.0625 lb./oz.) = $0.228/oz. At a 1/256 use
dilution the cleaning efficiency = 80.0% ##STR2## Cost per gallon
of use dilution product is $0.0114 Equal parts (1 oz. each) of
layers A and B are contained in one packet. This total 2ounce
product is diluted with 4 gallons water to yield a 1/25 use
dilution.
TABLE II ______________________________________ Homogeneous
Conventional All Purpose Cleaner Cost/Performance Data $ $ cost/ %
cost 100 lbs. ______________________________________ Water 60.0471
0.0001 0.0060 Potassium Carbonate 2.1982 0.315 0.6924 Potassium
Citrate 2.1982 0.84 1.8465 Nonyl phenol ethylene oxide 9.4483
0.5225 4.9367 Diethylene glycol monomethyl ether 3.9008 0.4900
1.9114 Isopropyl alcohol 5.5704 0.3089 1.7207 Propylene glycol
5.0348 0.3950 1.9888 Sodium Xylene Sulfonate 3.2137 0.2679 0.8610
Caustic Potash 2.5890 0.1895 0.4906 Perfume 0.135 4.000 0.54 Dye
0.0135 9.7080 0.1311 $15.1252
______________________________________ Cost per pound = 0.1512
(0.0625 lb./oz.) = $0.0094/oz. At a 1/20 use dilution cleaning
efficiency = 77.5% ##STR3## Cost per gallon of use dilution product
is $0.0602
EXPERIMENTAL PROCEDURE
The cleaning efficiencies reported in the preceding tables were
derived using a standard washability test. This test methodology is
a modified form of Federal Test Method Standard No. 536/670. The
methodology used is given below:
METHOD OF WASHABILITY
I. Panel Preparation
1. Read reflectance of white tile * with Photovolt Meter
(Rf=67.5)
2. Soil panels with standard soil (from federal test standard
method) using a 5 mil. film applicator.
3. Allow panels to age overnite (use within 1 week at most).
II. Washing of Panels
1. Make up 200 ml of use dilution cleaning solution for each tile
(run 2 tiles per solution).
2. Apply 50 ml to sponge in sponge holder. Pour remaining 150 ml.
to sponge in sponge holder. Pour remaining 150 ml over panel which
is clamped into the tray of the Gardner washability apparatus.
3. Soak panel in solution for 60 seconds.
4. Run sponge over panel for 50 cycles (100 strokes).
5. Remove panel and rinse off residue with tap water.
6. Dry for at least 30 minutes.
III. Calculation of Cleaning Efficiency (C.E.)
1. Set Photovolt Meter to 75% Rf with the green filter
inserted.
2. Read reflectance of panel at 3, 6, and 9 inches from top of
panel. Calculate average of these 3 numbers=Rf soiled.
3. Calculate C.E. by using equation Rf soiled/67.5.times.100=C.E.
%
* * * * *